Research on Reasonable Width of Coal Pillars of Non-equal Width Isolated Working Face Heading Goaf in Deep Mine

Setting reasonable coal pillar is a key to ensure safe mining of island coal face heading goaf in deep mine. With the background of typical deeply buried non-equal width isolated working face 3201 heading goaf in one mine and based on the spatial structure theory of overlying strata, the transformation of strata structure and the stress evolution of coal pillars caused therefrom in worked-out areas was analyzed, followed by a research on the mechanism of rock burst induced by coal pillars. As a result, it’s concluded that the fundamental cause of rock burst induced by coal pillars is that the high stress of coal pillars at critical state of a rock burst exceeds their comprehensive strength. By establishing a bearing and load model of coal pillars at a critical state of a rock burst, an method for estimating reasonable width of coal pillars of isolated working face in worked-out area was derived and applied to the non-equal width isolated working face 3201, thus determining that the reasonable width of coal pillars should be 130 m. The field practice verified the practicability of the method. The research result is of great significance to prevention and treatment of rock burst of isolated working face in worked-out area in deep mine.